Electrical jack and control means



J. E. CHAPMAN ELECTRliCAL JACK AND CONTROL MEANS Sept. 20, 1949.

2 Sheets-Sheet 1 Filed Sept. 25, 1942 Manual". JAMES E. CHAPMAN,

(Incl-neg;

Sept. 20, 1949. J. E. CHAPMAN ELdCTRICAL JACK AND CONTROL MEANS 2Sheets-Sheet 2 Filed Sept. 25, 1942 31wcntor Gttomeg Patented Se t. 20,1949 UNITED STATES PATENT. OFFICE James E. Chapman, Los Angeles, Calif"assignor to The Garrett Corporation, Airesearch Manufacturing Companydivision, Inglewood, Calm, a corporation of California ApplicationSeptember 25, 1942, Serial No. 459,731

My invention relates we power jack or extensible strut having particularutility in the operation of movable parts of aircraft. It is an objectClaims. (Cl. 192-142) of the invention to provide a simple and compactdevice having a motor body which is ordinarily attached to a stationarypart and an extensible 4 thrust bar which may be connected to the partvide a simple jack of the character described in the foregoing havingnovel means for operatin a control member in accordance with the move-.ment of the thrust-bar. This control member unay be associated with orembodied in a switch mounted directly upon the motor casing of thedevice,.wherein the control of the motor is correlated with movementofthe thrust bar through a prescribed range of movement.

A further object is to provide an electric jack 1 of this characterwhich is slender in form and therefore may be located in spaces ofcomparatively small size. By slender I intend to convey the meaning thatlateral extension of the motor body is maintained at a minimum.

A further object of the invention is toprovide a power operated jackhaving a reduction gear so formed and in such cooperative relation tothe motor and to the driven parts that slenderness and compactness areachieved.

A further object of the invention is to provide a jack wherein a motordriven part operates a screw which in turn reciprocates through a pathof movement a traveler arranged so that it will actuate switch meansemployed in the control of the 'motor of the device. Suchswitch meansmay be of any desired character and may cooperate in control circuits indiiierent ways, so long as the ultimate effect thereof is to produce acontrol of the operation of the motor in accordance with 'difierentpositions of the thrust bar of the Jack. For example, the switch meansmay be merely a limit switch, but is preferably a series type multipleswitch capable of use in the controlcircuits and system disclosed in thecopending application of Hannon, Serial No. 430,949, filed February 14,1942, now Patent No. 2,314,937.

Further objects and advantages of the invention 2 may be brought out inthe following part of the specification.

Referring to the drawings which are for illustrative purposes only,

Fig. 1 is a longitudinally sectioned view of the jack.

Fig. 2 is an enlarged cross sectional view taken as indicated by theline 2-2 of Fig. 1.

Fig. 3 is a fragmentary section taken as indicated by the line 3-3 ofFig. 2.

Fig. 4 is an enlarged fragmentary sectional view taken as indicated bythe line 4-4 of Fig. 1, to show a plan view of the switch mechanism.

Fig. 5 is a partly sectioned view showing an alternative form of switchmechanism for use in the .lack.

Fig. 6 is a slightly enlarged cross section taken as indicated by theline 66 of Fig. 5. I

Fig. 7 is a plan view of the series switch device shown in Figs. 5 and6.

The preferred embodiment of the invention shown in Fig. 1 includes asmall reversible motor.

It] included within a slender casing II which rotatably. supports adriven member [2 having threaded engagement with a thrust bar It whichwill move axially in response to rotation of the member I2. I

The motor ID has a rotor I 4 which drives the A member-12 through anovel arrangement of gears i5 disposed in a position surrounding theinner portion of thethrust bar. [3 when this thrust bar is in retractedposition as shown in Fig. 1. The driven member I2 is arranged to rotatea screw 16 which moves a traveler I! back and forth through a range ofmovement in accordance with the movement of the thrust bar I3 throughdifferent positions in its relatively larger range of movement. Thetraveler I1 cooperates or forms a part of a switch device S which isconnected into electrical circuits associated with the motor I. Themotor circuit forms no part of the presentinvention, and although theswitch device S may be a simple limit switch for stopping the motor whenthe thrust bar 13 approaches the end of its range of movement, theswitch device is so formed that it will cooperate in a control circuitsuchas disclosed in the copending application of Hannon, Serial No.430,949, previously referred to.

The motor Ili is built into the cylindric section 18 of the casing IIand includes field pieces l9. Thecylindric section It is clamped betweena cap 2| and the front section 22 of the casing H 'by means of screws20. The cap 21 has a pro- .iection 23 with an opening 24 therein wherebythe rear end of the casing II is connected to a stationary part. 7

Within the section 22 there is a radial wall II which supports a bearing26 in which a tubular member 26' is rotatable. The left or rear end ofthe tubular member 26' is rotatably supported in a bearing 21 carried bythe cap 2|. The tubular member 26' comprises the hollow shaft of therotor I4 and supports thereon the motor armature Z8 and the commutator29, both of which parts are diagrammatically indicated. The hollow shaft26 is of such size that the threaded thrust bar l3 may extend thereintowhen it is retracted as shown in Fig. 1.

The rightward end of the casing section 22 h threads 30 to receive anend member 3| which ha a projecting tubular portion 32 carrying b rings33 which'support the driven member II. The bearings 33 engage a threadedtubular porticn 34 of the driven member I2 and support the same forrotation on the axis of the casing {The driven member |2 includes acircular plate $35 at the inner end of the tubular portion 34, this!plate 35 supporting a short cylindrical section 36 comprising aninternal gear 31 and an external gear 38. The rightward end of thehollow shaft 25' projects beyond the bearing 26 and has a drive pinion39 formed thereon. This drive pinion engages planetary gears 40 whichare supported in outward relation relatively thereto by pins or axles 4|which are carried by a ring 42 supported for rotation around the axis ofthe shaft 26' by a ring bearing 43. A ring gear 44 is secured in thecasing section 22 in a position adjacent the ring bearing 43, this ringgear engaging the outwardly directed teeth of the planetary gears 40 sothat when the motor In is operated to rotate the pinion 39, theplanetary gears 40 will be caused to roll around the interior of thering gear 44. Second planetary gears 45 are rotatably supported on theaxles 4| and are directly connected to the planetary gears 40 so as tobe rotated thereby. The second planetary gears 45 are of a differentdiameter than the first planetary gears 40, and the teeth thereof engagethe internal gear 31 of the driven member i2. This difference indiameter of the first and second planetary gears 40 and 45 results in aslow rotation of the driven member I! as the planetary gears 40 rollthrough their circular path of movement within the internal gear 44.This reduction in thespeed at which the member I2 is driven as comparedto the motor speed is of course accompanied by a corresponding increasein torque applied to the driven member II. The threaded thrust member l3has a head 45 fixed thereon having an opening 4'! to receive a bolt orpin carried by the part which is to be moved by the jack. Accordingly,rotation of the threaded thrust bar I3 is prevented, and as the memberI! is rotated, the thrust bar I3 is caused to move axially, therebychanging the distance between the openings 24 and 41 and producingrelative movement of the parts to which the motor casing l and the head46 are respectively connected.

The screw I6 is supported on the casing section 22 by bearings 48. Asmall gear 49 is fixed on the screw l6 near the front end thereof, andthe lower portion of this gear 49 projects through an opening 50 in thecasing section 22 into engagement with the external gear 38 of thedriven member l2, so that the shaft IE will be given a rotationcorresponding to the rotation of the member I2, and the traveler H whichcomprises a nut in threaded engagement with the screw l8 will havemovement along the screw l4 co to themovement of thethrustbarllinaxialdireetion as the driven member I2 is rotated.

AsshowninFigs.2and4,aIu|debarl| is secured in parallel relation to thescrew II by screws 52, and on the outer face of this guide bar 5| a wall53 of insulating material is mounted. Spaced openings 54, through theguide bar II and the wall 53, receive thrust pins 55, the outer ends ofwhich engage spring contacts Ii. which are secured to the outer face ofthe wall 53. Each of these spring contacts 56 has a laterally extendedsupporting base 51, positioned so as to be engaged by the movable end ofthe preceding contact 65, whereby a series arrangement of these switchmembers is obtained. Referring to Fig. 3, a contact 53 is disposed atthe leftward end of the switch assembly, this contact being engageableby the first or left hand switch 5|. Progressing rightwardly through thearrangements of switches, it will be noted that each succeeding switch55 engages the base 51 of the preceding switch. a

The traveler has fingers 53 to engage the upper and lower faces of theguide bar 5|, as shown in Fig. 2, and the traveler I! has a cam facedtoward the guide bar 5| and having sloped ends 6|. This cam it forceseither one or two of the pins '55 outward, depending upon the positionof the cam in, thereby lifting corresponding switch members out ofengagement with the cooperating switch contacts formed by the baseportions II of other contacts 56, or the end contact 53, as

4 shown, for example, at 56' in Fig. 4. These seriesarranged switchescooperate with the circuits of a motor controlled system such as shownin said copending application, Serial No. 430,949, Patent No. 2,314,937,previously herein set forth. The jack is therefore adapted for usesunder conditions wherein a part is to be operated or controlled from aremote position.

In Figs. 5, 6, and 7 I show an alternative construction wherein screwthreads Ii, analogous to the screw l6 of the switch device 8, are formedon the tubular driven member I! which is analogous to the driven memberI! shown in Fig. 1. The jack shown in Fig. 5 embraces the motor casingII and the parts included therein, as will be indicated by theduplication in Fig. 5 of numerals employed in Fig. 1. The changes in thestructure are as follows. The front end cap 3| is replaced by an end cap3|" having an elongated tubular wall 32 to support the driven member12'. This wall 32' has an opening 02 alon a side thereof across whichthe switch plate ll, of nonconductive material is supported. A guide bar5| is supported on the inner face of the switch plate 63 in parallelrelation to the axis of the driven member l2 and thrust pins 55 areextended through the switch plate and the guide bar 5| as shown in Figs.5 and 6. The inner ends of the pins 55 are positioned so that they willbe engaged by a cam surface 60 formed'on an internally threaded travelerH which engages the screw threads |i', so as to be moved lengthwise ofthe driven member I! as the result of the rotation of this driven memberl2, the movement of the traveler being proportionate to the movement ofthe thrust bar l3 in consequence of the greater lead of the screwthreads formed on the thrust bar I3.

So as to be confined by a cover 65, switch parts 56a, 56b, and 58a aresecured on the outer face of the switch plate ii. The switch part Ila isa stationary contact which is engaged by the swingable end of a leafswitch 56a as shown at the left of Fig. 7. This leaf switch 56a has alateral extension 51a, and in series arrangement additional leafswitches 56a are arranged in rightward consecutive order along theswitch plate 63, with a simple leaf switch 561) at the rightward end ofthe switch plate 63. These leaf switches 56a and 56b are arranged overthe heads of the thrust or lift pins 55', whereby the leaf switches willbe lifted in consecutive order as the traveler l 'l' is moved from endto end of its range of movement.

I claim as my invention:

1. In a power jack of the character described, the combination of amotor having a rotor; an externally threaded thrust bar supported foraxial movement; an internally threaded driven member supported forrotation, the threads of said driven member engaging the threads of saidthrust bar; a connection to drive said driven member from said rotor ata reduced speed; an external screw on said driven member; a traveler inthreaded engagement with said external screw so that it will be movedthrough a path of movement in response to rotation of said drivenmemher; and switch means for control of said motor disposed contiguousto said path of movement so'as to be actuated by said traveler in timedrelation to the movement of said thrust bar.

2. In a power jack of the character described, the combination of: asupport having spaced bearings; a tubular member rotatably carried bysaid bearings, said tubular member having an internal thread and anexternal thread; motor means to rotate said tubular member; a thrust barextending within said tubular member and having threads to engage saidinternal threads of said tubular member so that rotation of said tubularmember will cause an axial movement of said thrust bar; a travelerhaving thread means to engage said external threads of said tubularmember so that rotation of said tubular member will cause movement ofsaid traveler through a short distance as said thrust bar is movedthrough a'relatively long distance by rotation of said tubular member;and switch means for controlling said motor comprising at least twoswitches and actuators for said switches disposed along the path ofmovement of said traveler so as to be engaged and operated by saidtraveler in a prescribed relation to the diflerent positions into whichsaid thrust bar is moved by rotation of said tubular member.

3. In a power jack of the character described, the combination of: asupport having spaced bearings, a member rotatably carried by saidbearings, said member having a first screw thread and a second screwthread; motor means to rotate said member; a thrust bar having threadsenga 1118 said first threads so that rotation of said member will causean axial movement or said thrust bar; a traveler having thread means toenmesaidsecondthreadsotsaidmemberso that rotation of said member willcause movement of said traveler through a short distance as .said thrustbar is moved through a relatively long 4. In a power jack of thecharacter described, a

combination of a motor; an externally threaded thrust bar supported forlongitudinal movement; a threaded driven member supported for rotation,the threads of said driven member engaging the threads of said thrustbar; connecting means be tween the motor and driven member; a secondscrew on said driven member; a traveler in threaded engagement with saidsecond screw so that it will be moved through a path of movement inresponse to rotation of said driven member; and switch means for controlof said motor, disposed contiguous to said path of movement so as to beactuated by said traveler.

5. In a power jack of the character described, the combination of: amotor having a rotor; an externally threaded thrust bar supported foraxial movement; an internally threaded driven member supported forrotation, the threads of said driven member engaging the threads of saidthrust bar; a connection to drive said driven member from said rotor; anexternal screw on said driven member; a traveler in threaded engagementwith said external screw so that it will be moved through a path ofmovement in response to rotation of said driven member; and switch meansfor control of said motor, said switch means including a series 01'movable members disposed contiguous to the path of movement of thetraveler so as to be successively actuated by said traveler inpredetermined relationship to the movement 01' said thrust bar.

JAMES E. CHAPMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 882,878 Ford Mar. 24, 19081,245,574 Dean Nov. 6,1917 1,325,010 Evarf Dec. 16, 1919 1,330,790 DeanFeb. 17, 1920 1,967,045 Wehmeyer July 17,1934 1,979,162 Lansing Oct. 30,1934 2,093,325 Lansing Sept. 14,1937 2,259,437 Dean Oct. 21,19412,279,220 Baum Apr. 7, 1942 2,283,476 Waibei May 19, 1942 2,307,317Konig Jan. 5,1943

